An Overview of the 2013 NOAA Hazardous Weather Testbed Spring Forecasting Experiment

Each spring, the Experimental Forecast Program of the NOAA/Hazardous Weather Testbed conducts a collaborative forecasting experiment. Organized by the Storm Prediction Center (SPC) and National Severe Storms Laboratory (NSSL), these annual forecasting experiments test emerging concepts and technologies designed to improve the prediction of hazardous mesoscale weather. The fundamental motivation for these experiments is to accelerate the transfer of promising new tools and concepts from research to operations and inspire new initiatives for operationally relevant research.

The 2013 Spring Forecasting Experiment (SFE2013) was conducted 6 May – 7 June. The major theme of SFE2013 was to explore the utility of short-term convection-allowing and mesoscale ensemble model guidance in creating frequently updated, high-temporal resolution probabilistic forecasts of severe weather. For SFE2013, a suite of new and improved experimental mesoscale and convection-allowing model (CAM) guidance was available for the generation of these forecasts. The new guidance included the NSSL Mesoscale Ensemble (NME), an EnKF-based 18-km grid-spacing, 36 member analysis and forecast system; a parallel NSSL WRF-ARW initialized from the NME; 12 UTC-initialized convection-allowing ensembles; and two CAM runs (i.e., 4.4- and 2.2-km grid spacing) from the Unified Model of the UK Met Office (UKMET) through a new collaborative endeavor.

During SFE2013, a variety of forecast and evaluation activities were conducted to address several primary goals: 1) assess the value of updating convective outlooks valid for 3-hour periods, 2) compare 12 UTC-initialized convection-allowing ensembles to their 00 UTC-initialized counterparts, 3) evaluate the NME in diagnosing and predicting the pre-convective environment, 4) determine whether the parallel NSSL WRF-ARW initialized from the NME produces improved forecasts over the NAM-initialized version, and 5) investigate the UKMET Unified Model convection-allowing runs for performance differences with the WRF-ARW runs. A summary of the preliminary findings and results of SFE2013 is presented along with the potential operational impacts.